MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 (01) PDF DOCUMENT

Always read and observe the following safety precautions before installation and electrical work for your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3.

WARNINGS (risk of serious injury or death):

• Do not use any refrigerant other than the type specified (R410A) on the unit’s nameplate and in the manuals. Using the wrong refrigerant can cause the unit or pipes to burst, leading to explosions or fires.

• Installation should only be performed by your dealer or a qualified technician. Improper installation can lead to water leakage, electric shock, or fire.

• Install the unit on a surface strong enough to support its weight to prevent it from falling and causing injury.

• Use only specified cables and connect them securely, ensuring the terminals do not bear the cable’s weight. Improper connections can generate heat and cause a fire.

• Take appropriate measures against wind and earthquakes to prevent the unit from toppling over.

• Use only accessories (like air cleaners, heaters) recommended by Mitsubishi Electric. Do not make any modifications to the unit.

• Do not touch the heat exchanger fins with bare hands as they are sharp and can cause cuts.

• If a refrigerant leak occurs, ventilate the room thoroughly. If the leaked gas contacts an open flame, toxic gases will be generated.

• Have all electrical work done by an authorized electrician according to local regulations, using a dedicated circuit. Insufficient power supply or improper installation can cause malfunctions, electric shock, or fire.

• Keep electrical parts away from water, as wet parts pose a risk of electric shock, smoke, or fire.

• Securely attach the control box cover to prevent dust or water from entering, which could cause electric shock, smoke, or fire.

• When installing in a small space, take precautions to prevent leaked refrigerant from exceeding the limiting concentration, which can cause oxygen starvation.

• After service work, always check for refrigerant leaks.

• Do not attempt to defeat safety features like pressure or temperature switches.

• Consult your dealer for proper disposal methods.

When working with the MITSUBISHI ELECTRIC PEFY-P15NMAU-E3, which uses R410A refrigerant, please observe the following precautions:

• Do not use existing refrigerant piping. Residual chlorine from old refrigerant and oil can cause the new unit’s refrigerator oil to deteriorate.

• Only use R410A refrigerant. Other refrigerants containing chloride will cause the refrigerator oil to deteriorate.

• Use refrigerant piping made of phosphorus deoxidized copper. Keep the inner and outer surfaces of pipes clean and free from contaminants like sulfur, dust, dirt, and moisture.

• Use a vacuum pump equipped with a check valve to prevent vacuum pump oil from flowing back into the refrigerant cycle.

• Store piping materials indoors and keep both ends sealed until brazing to prevent dust, dirt, or water from entering the system.

• Use tools exclusively for R410A (gauge manifold, charging hose, gas leak detector, check valve, etc.). Contamination from conventional refrigerants can cause the oil to deteriorate.

• Use a small amount of ester oil, ether oil, or alkyl benzene to coat flares and flanges. A large amount of mineral oil can cause deterioration.

• Do not use a charging cylinder. Its use can alter the composition of the refrigerant, making it unsuitable.

• Always charge the system with refrigerant in its liquid phase. If charged in a gaseous phase, the refrigerant composition in the cylinder will change.

The buttons on the PAR-21MAAU remote controller for your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 have the following functions:

Note: Keep the remote controller out of direct sunlight and ensure the thermistor at the lower right-hand section is not obstructed for accurate room temperature measurement.

The display on the PAR-21MAAU remote controller for your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 shows the following information:

To operate your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 in Cool mode, follow these steps:

1. Press the POWER [ON/OFF] button to turn the unit on.

2. Press the operation [Mode] button until the COOL symbol is displayed.

3. Press the [Set Temperature] button to select your desired temperature. The temperature changes by 2°F with each press, within a range of 67°F to 87°F.

Cool Mode Functions:

• Thermoregulating Function: The unit will turn on cooling (Thermo ON) when the room temperature is 2°F above the set temperature and turn off cooling (Thermo OFF) when the room temperature is at or below the set temperature. There is a 3-minute delay to prevent restarting too quickly.

• Anti-freezing Control: If the liquid pipe temperature (TH22) drops to 33.8°F or less within 16 minutes of the compressor starting, the anti-freezing control activates, and the unit enters Thermo OFF. This control is canceled when the liquid pipe temperature rises to 50°F or above, among other conditions.

• Fan Control: You can select between [Low], [Med], [High], and [Auto] fan speeds. In [Auto] mode, the fan speed adjusts based on the difference between the room temperature and the set temperature.

• Drain Pump Control: The drain pump runs continuously during Cool mode. When you switch out of Cool mode or stop the unit, the drain pump continues to run for 3 minutes to clear any remaining condensation.

• Float Switch Control: The system monitors the float switch to detect water levels. If the float switch is detected as ON for 15 consecutive seconds, it indicates water is present.

To use the Dry mode for dehumidification on your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3, follow these instructions:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button until the DRY symbol is displayed.

3. Use the [Set Temperature] button to set the desired temperature. The temperature changes by 2°F with each press, within a range of 67°F to 87°F.

Dry Mode Functions:

• Thermoregulating Function: The unit cycles on and off based on room temperature to control humidity. The ON/OFF cycle times vary depending on the current room temperature, as shown in the table below.

• Fan Control: The fan operation depends on the compressor status.

• Drain Pump Control: The drain pump control is the same as in Cool mode.

To use the Fan only mode for air circulation with your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display the FAN symbol.

Fan Mode Functions:

• Fan Speed: You can select from [Low], [Med], [High], and [Auto] fan speeds. When [Auto] is selected in Fan mode, the fan speed will default to [Low].

• Drain Pump Control: The drain pump will run for a specified time under certain conditions:

1. It runs for 3 minutes after the operation mode is switched from COOL or DRY to FAN mode.

2. It runs for 6 minutes if the float switch control detects that the sensor is submerged in water.

Note: Temperature setting is not available in Fan mode.

To operate your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 in Heat mode, follow these instructions:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display the HEAT symbol.

3. Use the [Set Temperature] button to set the desired temperature. Each press changes the temperature by 2°F, within a range of 63°F to 83°F.

Heat Mode Displays:

• [DEFROST]: This symbol appears only during the defrost operation of the outdoor unit.

• [STANDBY]: This symbol is displayed during the hot adjust mode.

Heat Mode Functions:

• Thermoregulating Function: Heating turns on (Thermo ON) when the room temperature is 2°F below the set temperature. Heating turns off (Thermo OFF) when the room temperature is at or above the set temperature.

• Fan Control: You can select [Low], [Med], [High], or [Auto] fan speeds. In [Auto], the speed changes based on the difference between the desired and room temperatures. The fan control prioritizes the following modes:

1. Hot adjust mode: At the start of heating, the fan runs at [Extra Low] and then [Low] before switching to the remote controller’s set speed to prevent cold drafts. “STAND BY” is displayed during this time.

2. Preheating exclusion mode: When an auxiliary heater turns off, the fan runs at [Low] for 1 minute.

3. Thermo OFF mode: When heating is off due to thermoregulating, the fan runs at [Extra low].

4. Heat defrosting mode: The indoor fan stops during defrost.

• Drain Pump Control: The drain pump operates under the same conditions as in Fan mode.

The Auto mode on your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 automatically selects between Cool and Heat modes to maintain your desired temperature. To use it:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button until AUTO is displayed.

3. Use the [Set Temperature] button to set your desired temperature (range is 67°F to 83°F).

How Auto Mode Works:

• Initial Operation: When started, the unit will enter HEAT mode if the room temperature is less than the desired temperature, and COOL mode if the room temperature is greater than or equal to the desired temperature.

• Mode Change:

– The unit will switch from HEAT to COOL mode if the room temperature becomes greater than the desired temperature + 3°F for 3 minutes.

– The unit will switch from COOL to HEAT mode if the room temperature becomes less than or equal to the desired temperature – 3°F for 3 minutes.

• Operation in COOL or HEAT: Once a mode is selected, the unit operates with the same controls and functions as if it were manually set to Cool or Heat mode.

When your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 unit is stopped, the drain pump may still operate to remove residual condensation under the following conditions:

1. The drain pump will run for 3 minutes after the operation mode is switched from COOL or DRY to another mode (like FAN) or stopped completely.

2. The drain pump will run for 6 minutes if the float switch control detects that its sensor is submerged in water, even if the main unit operation is off.

To check the room temperature thermistor (TH21), liquid pipe thermistor (TH22), and gas pipe thermistor (TH23) on your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3, follow these steps:

1. Turn off the power to the unit.

2. Disconnect the thermistor’s connector from the control board.

3. Using a multimeter, measure the resistance between the terminals of the connector.

4. Compare the reading to the expected values. In a typical ambient temperature range of 50°F – 86°F (10°C – 30°C), the resistance should be between 4.3 kΩ and 9.6 kΩ.

• If the reading is within this range, the thermistor is likely functioning normally.

• If the reading is open (infinite resistance) or short (zero resistance), the thermistor is abnormal and should be replaced.

Reference Resistance Values:

To test the linear expansion valve (LEV) on your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3, you need to check the resistance of its motor coils.

1. Turn off all power to the air conditioning unit.

2. Disconnect the LEV connector (CN60) from the indoor control board.

3. Use a multimeter to measure the resistance between the pins of the connector as specified below.

• Measure between pins 1 (White) and 5 (Red).

• Measure between pins 2 (Yellow) and 6 (Brown).

• Measure between pins 3 (Orange) and 5 (Red).

• Measure between pins 4 (Blue) and 6 (Brown).

4. The normal resistance for each of these coil pairs should be approximately 200 kΩ ±10%.

If any reading is open (infinite resistance) or short (zero resistance), the LEV is faulty and needs to be replaced.

Checking the Drain-up Mechanism (Drain Pump)

1. Disconnect the power to the unit.

2. Locate the drain pump connector on the control board.

3. Measure the resistance between terminals 1 and 3 with a multimeter. At a coil temperature of 68°F (20°C), the normal resistance should be approximately 340 Ω. If the reading is open or short, the drain pump is faulty.

Checking the Drain Float Switch (CN4F)

1. Disconnect the power to the unit.

2. Disconnect the drain float switch connector (CN4F) from the control board.

3. Use a multimeter to check the continuity between the terminals while manually moving the float.

• When the float is in the Up position (indicating high water level), the switch should be Short (closed circuit, showing continuity).

• When the float is in the Down position (normal), the switch should be Open (open circuit, no continuity).

If the switch does not operate as described, it is abnormal and should be checked or replaced.

If the indoor unit fan on your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 does not run, follow these troubleshooting steps. CAUTION: High voltage is present at the fan motor connector (CNMF). Do not unplug it while the unit is energized.

1. Check Connector: Ensure the fan motor connector (CNMF) is fully and securely inserted into the control board. If not, fix the connection.

2. Check Power Supply Voltage: If the connection is secure, check the DC voltages at the connector on the indoor control board.

• VDC: Measure the voltage between pin 1 (+) and pin 4 (-). It should be between 294VDC and 340VDC.

• Vcc: Measure the voltage between pin 5 (+) and pin 4 (-). It should be 15VDC.

• Vsp: Measure the voltage between pin 6 (+) and pin 4 (-). It should be between 1VDC and 6.5VDC while the fan is in operation (0V when stopped).

If these voltages are not within the normal range, replace the indoor control board.

3. Check Position Signal: If voltages are normal, check the fan motor position thermistor signal (VFG).

• With the motor supposed to be running, measure the voltage at the test point VFG, or between pin 7 (+) and pin 4 (-) on the connector.

• The voltage should alternate between 0VDC and 15VDC as the motor rotates.

4. Determine Fault:

• If the VFG signal does not alternate between 0VDC and 15VDC, the fan motor is likely faulty. Replace the motor.

• If the VFG signal alternates correctly but the motor does not run, the issue is with the control logic. Replace the indoor control board.

To ensure your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 unit runs correctly within a system, you must set its address. Always turn off the power to the unit before changing switch settings.

1. Locate the rotary switches SW11 and SW12 on the indoor unit control board.

2. SW12 is used to set the 10’s digit of the address, and SW11 is used to set the 1’s digit.

3. Using a small screwdriver, turn the rotary switches to the desired address number. The address settings vary depending on the system configuration; refer to the outdoor unit installation manual for the correct address scheme.

Examples:

• To set the address to “3”, set SW12 to “0” and SW11 to “3”.

• To set the address to “25”, set SW12 to “2” and SW11 to “5”.

Note: Address setting is required when using an ME remote controller. On-site address setting is required for the indoor units to run.

The SW1 dipswitch on the control board of your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 configures various functions. Settings must be made while the unit is stopped. The factory setting is all OFF.

The SW3 dipswitch on your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 is used to set the unit type, heater backup, and heating performance. Settings must be made while the unit is stopped. The factory setting is all OFF.

To match the fan performance of your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3 to your ductwork’s requirements, you can set the external static pressure using the SWA and SWC dipswitches on the indoor control board. Changes to these switches take effect immediately, regardless of the unit’s operating status.

The factory setting is 50Pa (0.20in.WG).

To remove the control box cover on your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3, please exercise caution as parts can be heavy. Follow these steps:

1. Ensure all power to the unit is turned off and disconnected.

2. Locate the control box cover.

3. Remove the three fixing screws on the cover to release it.

4. Lift the cover off the unit.

When reinstalling, tighten the screws to a torque of 2.0±0.2 N.m.

To remove the intake air thermistor (TH21) from your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3:

1. Turn off power and remove the control box cover as described in the control box disassembly procedure.

2. Locate the thermistor holder and the thermistor on the control box.

3. Simply pull out the thermistor holder and the thermistor from their position on the control box.

Please exercise caution when removing heavy parts. Before you begin, ensure the water is completely drained from the drain pan to prevent spills.

1. Remove the Filter and Bottom Plate

(1) Push down the tab on the air filter and pull the filter out in the direction of the arrow (1).

(2) Remove the fixing screws on the bottom plate to detach it from the unit. When reinstalling, tighten these screws to a torque of 1.4±0.2 N.m.

2. Remove the Drain Pan

(1) With the bottom plate removed, pull the drain pan straight out in the direction of the arrow (2) to remove it from the unit.

To remove the gas pipe thermistor (TH23) or liquid pipe thermistor (TH22) on your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3, follow these steps, exercising caution with heavy parts:

1. Remove the drain pan following the appropriate disassembly procedure.

2. Locate the heat exchanger cover. Remove the four fixing screws holding it in place and remove the cover. When reinstalling, tighten these screws to a torque of 1.4±0.2 N.m.

3. The thermistors are clipped onto the copper pipes with a holder. To remove a thermistor, simply unclip it from its holder on the respective copper tube (liquid or gas pipe).

Exercise caution when removing heavy parts. To disassemble the fan and fan motor of your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3, follow this procedure:

1. Remove Filter and Bottom Plate:

(1) Push the tab on the filter and pull it out.

(2) Remove the fixing screws on the bottom plate and remove it. Re-tighten screws to 1.4±0.2 N.m upon reassembly.

2. Remove Fan Casing (Bottom Half):

(1) Squeeze the tabs on the bottom half of the fan casing and pull it out in the direction of arrow 2.

3. Remove Motor Cable:

(1) Remove the motor cable through the rubber bush.

4. Remove Fan Motor and Sirocco Fan:

(1) Remove the two motor fixing screws. This will allow you to remove the motor and the attached Sirocco fan assembly. Re-tighten these screws to 3.5±0.2 N.m upon reassembly.

5. Separate Fan Casing (Top Half):

(1) To fully remove the top half of the fan casing, remove the four fan case fixing screws. Re-tighten these screws to 1.4±0.2 N.m upon reassembly.

To remove the heat exchanger from your MITSUBISHI ELECTRIC PEFY-P15NMAU-E3, please exercise caution as it is a heavy component. You will need to perform some preliminary disassembly first.

1. Remove the drain pan according to its disassembly procedure.

2. Remove the heat exchanger cover according to its disassembly procedure (this involves removing four screws).

3. Remove the Pipe Support Plate Cover:

(1) Remove the five fixing screws on the cover (K), which acts as a pipe support plate, to remove it. When reinstalling, tighten these screws to a torque of 2.0±0.2 N.m.

4. Remove the Heat Exchanger:

(1) With the covers removed, remove the fixing screws on the heat exchanger itself (M) to detach and remove it from the unit’s chassis. When reinstalling, tighten these screws to a torque of 1.4±0.2 N.m.